1. Technical Field
The present disclosure relates to an electronic article surveillance (EAS) system. More particularly, the present disclosure relates to an EAS system for exciting an EAS marker in a wide exit/entrance environment.
2. Background of the Related Art
Electronic Article Surveillance (EAS) systems are detection systems that allow the identification of a marker or tag within a given detection region. EAS systems have many uses, but often are used as a security system. Such a security system is for preventing shoplifting, robbery and theft in stores or the removal of property in office buildings; however such systems have been extended to other areas. Such areas include monitoring consumer habits and inventory control. EAS systems come in many different forms and make use of a number of different technologies.
An EAS system includes an electronic detection unit, markers and/or tags, and a detacher or deactivator. The detection units can, for example, be formed as pedestal units, buried under floors, mounted on walls, or hung from ceilings. The detection units are usually placed in high traffic areas, such as entrances and exits of stores or office buildings. The markers and/or tags have special characteristics and are specifically designed to be connected to, or embedded in, merchandise or other objects sought to be protected. When an active marker passes through a marker detection region, the EAS system sounds an alarm, a light is activated, and/or some other suitable audible alert device is activated to indicate the removal of the marker from the prescribed area.
Common EAS systems use transceivers. Transceivers each transmit and receive signals, or are made of a discrete and separate transmitter and receiver. The transmitter or one transceiver is placed on one side of the detection region. The receiver or another transceiver is placed on the opposite side of the detection region. The transmitter produces a predetermined excitation signal in a marker detection region.
This detection region is usually formed at a checkout aisle or an exit, or at an entrance. When an EAS marker enters the detection region, the marker has a characteristic response to the excitation signal. The characteristic response is received and detected by the system.
The marker may respond to the signal sent by the transmitter by using a simple semiconductor junction, a tuned circuit with an inductor and capacitor, a soft magnetic strip or wire, or a vibrating resonator.
The receiver subsequently detects this characteristic response. By design, the characteristic response of the marker is distinctive. The response is not likely to be created by natural circumstances. Moreover, such other noise or other signals may be filtered out using an appropriate filtering device connected to the EAS system.
EAS systems are often called upon for coverage of a large detection area, such as larger retail, commercial or storage establishments. Such retail establishments are often located in a mall or other strip malls. Often the mall will have an opened exit. The exit is larger and wider that conventional store entrances and exits. The mall store entrance can sometimes cover the width of the mall store itself. Such relatively large detection areas require special design considerations.
The EAS system used for coverage should be carefully designed to avoid any gaps where there is little or no magnetic field through which an EAS marker might pass through undetected.
Simultaneously, such an EAS system should avoid false alarming. Such false alarming distracts workers. False alarms may be caused by markers attached to store inventory which may be displayed near or adjacent to the detection region. It has been observed that when conventional EAS antenna systems, typically formed of loop antennas, are used in openings wider than about two meters, detection performance begins to deteriorate making exits greater than two meters.
Wide mall store entrances/exits may need detection areas up to about six meters wide or more. Wide exits and wide entrances refer to exits/entrances having widths greater than or equal to about 2.0 meters.
Attempts at solutions to the wide entrance environment include adding additional antennas in the floor and/or ceiling. However, this is disfavored because of the expensive construction costs associated with such an installation in the floor and/or ceiling. Adding loop antennas in existing flooring causes many problems, as the floor must be torn up in order to install the loop antenna, then replaced.
Additionally, such EAS systems often have to be permanently installed into the store. If installation requires a retrofit into the existing space, often the store's normal operation may be disturbed during installation, i.e., the floor or ceiling will have to be opened for installation of the EAS system then fixed and restored. Thereafter, if a modification of the entrance or exit occurs, any alteration of the orientation or location of the EAS system is desired (such as if an exit becomes wider), a major amount of work may be required. It would be desirable to provide a modular EAS system that can be easily installed, removed or moved depending on changing store condition or configuration.
Accordingly, there is a need for an EAS system that eliminates one or more of the aforementioned drawbacks and deficiencies of the prior art.